I've been looking into this, and as far as I can tell, it entered common use through a comic in the 50's, though I haven't found which one. Recently, though, I've been reading a book called Mao, in which there is some discussion about a spy who played a critical role in the Battle of Shanghai in 1937. What's interesting about him is that he was a sleeper spy who had been planted by the Russians in the CCP army years before he was stationed in Shanghai--and his initials were ZZZ. Whether he is related to the use of "zzz" to mean sleep, I don't know, but I found it very interesting.
Probably one of 2 theories: From the illustration of cartoons, where a sleeping person is shown with "zzzzzz" above their head. or "Logging Zs" was an older phrase, from "sawing logs" or snoring. It may have been updated to "catching Zs" since then.
Thermoses complete explanation courtesy of Purdue University Brought to you by the Purdue University Online Writing Lab ---- 1. Add an -s to form the plural of most words. * elephant--elephants * stereo--stereos 2. For words that end in a "hissing" sound (-s, -z, -x, -ch, -sh), add an -es to form the plural. * box--boxes * church--churches 3. If the word ends in a vowel plus -y (-ay, -ey, -iy, -oy, -uy), add an -s to the word. * tray--trays * key--keys 4. If the word ends in a consonant plus -y, change the -y into -ie and add an -s to form the plural. * enemy--enemies * baby--babies 5. For words that end in -is, change the -is to -es to make the plural form. * synopsis--synopses * thesis--theses 6. Some words that end in -f or -fe have plurals that end in -ves. * knife--knives * self--selves 7. The plurals of words ending in -o are formed by either adding -s or by adding -es. The plurals of many words can be formed either way. To determine whether a particular word ends in -s or -es (or if the word can be spelled either way), check your dictionary or the list below. There are two helpful rules: a. All words that end in a vowel plus -o (-ao, -eo, -io, -oo, -uo) have plurals that end in just -s: * stereo--stereos * studio--studios * duo--duos b. All musical terms ending in -o have plurals ending in just -s. * piano--pianos * cello--cellos * solo--solos c. Plural forms of words ending in -o: -os-oes-os or -oes : albinos : armadillos : autos : bravos : broncos : cantos : casinos : combos : gazebos : infernos : kimonos : logos : maraschinos : ponchos : sombreros : tacos : torsos : tobaccos : typos : echoes : embargoes : heroes : potatoes : tomatoes : torpedoes : vetoes : avocados/oes : buffaloes/os : cargoes/os : desperadoes/os : dodoes/os : dominoes/os : ghettos/oes : grottoes/os : hoboes/os : innuendoes/os : lassos/oes : mangoes/os : mosquitoes/os : mottoes/os : mulattos/oes : noes/os : palmettos/oes : peccadilloes/os : tornadoes/os : volcanoes/os : zeros/oes 8. The plurals of single capital letters, acronyms, and Arabic numerals (1,2,3,...) take an -s WITHOUT an apostrophe: * Z (the capital letter Z)--Zs * UPC (Universal Product Code)--UPCs * ATM (Automatic Teller Machine)--ATMs * GUI (Graphical User Interface)--GUIs * 3 (the Arabic numeral 3)--3s
Probably one of 2 theories: From the illustration of cartoons, where a sleeping person is shown with "zzzzzz" above their head. or "Logging Zs" was an older phrase, from "sawing logs" or snoring. It may have been updated to "catching Zs" since then.
zigzag
ZS Associates's population is 1,500.
ZS Associates was created in 1983.
MG ZS was created in 2001.
there is no animal with double Zs.
zs
The MG ZS is a family sports car, and was created from BMW's Rover 45, which MG purchased the rights to. The first MG ZS was produced and launched in 2001, the last in 2005.
The following word contains more than 2 zs :- 'Zigzag'
Blizzard
Yes the Sony ZS-H10CP is rugged enough for a construction site, it is also water resistant.
Various used models of MG ZS can be found in Toronto on several websites for used vehicles. The most popular websites are Kijiji Toronto, autoTRADER, and Auto Catch.